In disc brakes, such as illustrated in U.S. Pat. Nos. 4,446,948, 5,526,904, 5,562,187 and 5,785,156 wherein guide pins are provided to accommodate sliding motion between a carrier member and a caliper the elimination of noise caused by rattling of components is a concern.
One way of reducing noise is through rubber bushings as disclosed in U.S. Pat. No. 4,446,948 which insulate guide pins. In addition, compensation for manufacturing tolerances can be achieved by tightly align one guide pin in a first bore while allowing a second guide pin to be loosely retained in a second bore as disclosed in U.S. Pat. No. 5,526,904. In this arrangement a resilient guide bushing which surrounds a portion of the second guide pin to sustain a desired alignment between friction pads and a rotor.
Further, noise caused by rattling of the components in a disc brake have been greatly reduced through the use of resilient projection extending from the guide pins to retain the components in engagement as disclosed in U.S. Pat. No. 5,562,187. Unfortunately, such pins are costly to produce and as a result have not yet been endorsed by the industry.
While the resilient bushings and special guide pins disclosed in the prior art function in a satisfactory manner, it has been observed that radial forces developed when a disc brake is subjected to vibration such as experienced in travel on rough roads are different that tangential forces caused by dynamic loading during a brake application.
In the present invention, guide pins retained in a carrier member are aligned within bores in caliper by relatively low cost and easy to manufacture bearing means having dissimilar resistance's to stiffness in a radial plane than in a tangential plane. The bearing means is designed to attenuate vibratory forces and resultant noise while allowing tangential forces created by dynamic forces generated during a brake application to be absorbed such that the friction pads and rotor are maintained in a desired alignment.